Byssus drifting and the drifting threads of the young post-larval mussel Mytilus edulis
Lane, D.J.W.; Beaumont, A.R.; Hunter, J.R. (1985). Byssus drifting and the drifting threads of the young post-larval mussel Mytilus edulis. Mar. Biol. (Berl.) 84(3): 301-308. http://dx.doi.org/10.1007/BF00392500
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
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| Authors | | Top |
- Lane, D.J.W.
- Beaumont, A.R., more
- Hunter, J.R.
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| Abstract |
The long, drifting threads secreted by young post-larval mussels (Mytilus edulis L.) are simple monofilaments, distinct in form and function from the attachment byssus threads. The diameters of both thread types are in the micron or sub-micron range but, whereas the attachment threads are of restricted length and terminate in an attachment plaque, drifting threads exceed the postlarva in length by more than two orders in magnitude and are without plaques or any other structures. Transmission electron micrographs of drifting threads show no evidence of internal substructure. In contrast, attachment threads appear to be made up of filaments. These studies confirm that the drifting threads are highly etfective in enhancing the dispersal of young mussels. The terminal sinking velocity of young drifters is typically ca. 1mm S-1. At this velocity the suspension range above the sea bed, assuming given values of verticaI diffusivity, is estimated to be 0.5 to 5 m. Calculations of the fluid drag experienced by post-larvae in the water column show that the theoretical viscous drag force on the thread is sufficient to account for the reduced sinking rate of drifters. The calculated contribution of the thread to the total drag is approximately one order of magnitude greater than that of the post-larval body. A rapid thread-deployment strategy, shown by postlarvae which are brought into suspension, may prolong each drifting excursion and thus further enhance dispersal in turbulent marine environments. |
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